Reproduction Number

Explanation :

• Also called the basic reproduction number, it indicates the average number of people who will contract the virus from a person who has already been infected, in a population that does not have immunity for the said disease.
• R0 is the division of the number of new infections by the number of existing infections, or the average number of new infections over an infectious period (R0= new infections/existing infections).
• To illustrate with an example, if the number of people diagnosed with a disease increases from four to eight in two days, it is likely to increase to 16 two days later, or in four days from the start. This makes the R0 two.

R0 Values

Three possibilities exist for the potential spread or decline of a disease, depending on its R0 value:

• If R0 is less than 1, each existing infection causes less than one new infection. In this case, the disease will decline and eventually die out.
• If R0 equals 1, each existing infection causes one new infection. The disease will stay alive and stable, but there won’t be an outbreak or an epidemic.
• If R0 is more than 1, each existing infection causes more than one new infection. The disease will spread between people, and there may be an outbreak or epidemic.
• The higher the R0, the more contagious the infection.